The semiconductor integrated circuit (IC) industry has experienced rapid growth. Technological advances in IC materials, design, and fabrication tools have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. In the course of these advances, fabrication methods and materials have been developed to realize the desire for smaller feature sizes.
One development being considered for the enhanced performance of devices is the use of silicon germanium to form the channel of some devices such as PMOS field effect transistors (PFET devices), while silicon is maintained for the use of NMOS field effect transistors (NFET devices). Intermixing device types on the same substrate provides challenges in their integration however. For example, materials that may benefit one device type may be detrimental to another device type. Thus, methods that adequately address multiple device types on a single substrate while maintaining or increasing the performance are desired.